1. Field of the Invention
The present invention relates to a settling judgment method and a positioning control device for judging whether a target is settled in or following to a target position in a positioning control device for moving an object to a target position by an actuator, and more particularly to a settling judgment method for a positioning control device and the positioning control device for decreasing the time required settling judgment and performing the settling judgment accurately.
2. Description of the Related Art
Positioning control devices for moving an object to a target position are widely used. High precision positioning is required for positioning control devices used for disk devices. Particularly to a magnetic disk device and optical disk device, accurate positioning of the head to the target track is extremely important to improve recording density. A method for judging whether positioning control to the target position is being performed accurately is settling judgment.
In the settling judgment of positioning control devices, positioning control parameter after movement or after position is shifted must satisfy predetermined positioning conditions during a predetermined time. In the case of a magnetic disk device, for example, settling judgment after seek control and settling judgment during follow up control are performed. In these settling judgments it is judged that settling has completed when the value of the judgment formula based on the position error continuously satisfies being in a predetermined slice range, and the continuing count is more than a predetermined count (sample count).
As a method for this settling judgment, a method for estimating the position of the next sample (Japanese Patent Application Laid-Open No. H08-106742) and a method for applying an estimated position using an observer (Japanese Patent Application Laid-Open No. H04-298868) have been proposed.